Copper sweetening hydrocarbon oils



I Patented Oct. 13, 1942 COPPER. SWEETENING HYDROCABBON OILS Davis Read,Jr., and Wayne L; Benedict, Chicago,

IIL, assignors to Universal Oil Products Compauy, Chicago, 111., acorporation of Delaware No Drawing. Original application August 18,

1939, Serial No. 290,846.

Divided and this application May 31, 940, SerialNo. 338,224

ZCIaims.

This invention, which is a division of our copending application SerialNo. 290,846, filed August 18,1939, relates to a method of manufacturingan improved treating reagent useful for improving the odor and stabilityof hydrocarbon distillates in general and particularly those boilingwithin the gasoline boiling range. The lrvdrocarbondistillates which maybe treated according to the present invention may be ob tained by thestraight run distillate or by the cracking of higher boiling hydrocarbonoils. The source of such oils may be coal tar oil, shale oil and thelike, but is usually from crude petroleum oil and similar sources.

Practically all petroleum distillates require some form of refining inorder to produce a marketable product. This is particularly true ofgasoline which requires some form of treatment to improve the odor,prevent deterioration in storage, eliminate corrosion of metal partswith which the gasoline is likely to come in contact, etc.

Many distillates require only asweetening treatment with or without theaddition of inhibitors to improve storage stability. Among the processespracticed for this purpose is the sodium plumbite process, thehypo-chlorite process and various modifications of the so-called coppersweetening process. It is with improvements in the latter that thepresent invention is concerned.

In one specific embodiment the present invention comprises a method formanufacturing a copper sweetening reagent which comprises mixing aheated porous filler such as pumice, fuller's earth, firebrick and thelike with a heated solution of copper sulfate and an alkalinous chloridewherein the weight ratio of copper sulfate to said chloride is withinthe range of approximately 50:50 and 67:33 under conditions such that amajor portion of the water contained in said solution is evaporated,thereby producing an active copper sweetening agent.

The impregnation of relatively inert fillers with copper salts toproduce sweetening reagents has been practiced previously. However, wehave discovered when using fillers impregnated with mixtures of coppersulfate and an alkalinous chloride that the weight ratio of the coppersulfate to said chloride is critical if the best results are to beobtained. The critical limits of these weight ratios are within theapproximate values of 50 parts copper sulfate to 50 parts alkalinouschloride, and 67 parts copper sulfate to 33 parts alkelinous chloride.In certain cases when using reagents outside this range, little or nosweetening can be obtained with the reagent, while in other cases thereagent sweetens but is found to have limited life. In still otherinstances, the reagent sweetens the d stillate but is found to produce aproduct of inferior quality.

The term alkalinous chloride is defined as includingthe chlorides ofalkali or alkaline earth metal chlorides as well as of the hypotheticalmetal ammonium. Equivalent halides such as the bromide may also be used.

The reagent of the present invention is prepared by the impregnation ofa spacing agent or filler such as pumice or .fuller's earth or otherporous, relatively inert materials, with the chemicals mentioned. Theimpregnation is suitably carried out by the following method: Thefiller, such as 6-20 mesh pumice, is heated to a temperature ofapproximately 250-400 F., and preferably to about 350. F. The coppersulfate and alkalinous chloride, such as ammonium chloride, in thedesired proportions are dissolved in water at a temperature ofapproximately -200" F. The strength of the solution should be such thatno precipitation of salt occurs at the temperature used but should be'asnearly saturated with the mixed salts as possible. The hot solution andthe hot filler are rapidly and intimately and uniformly mixed by anysuitable method such as spraying the solution on the filler underconditions such that rapid evaporation of the water takes place. A blastof air may be passed over the heated mixture in order to carry awaywater vapor as it is evolved and to dry the reagent to the desiredpoint. The reagent should contain approximately 5-20% of moisture whenfinished.- The quantity of salts deposited on the filler may varyconsiderably. Normally, there should be sufiicient saltso that the totalreaction mixture analyzes 1-5% copper. Satisfactory reagents have beenmade containing between 2 and 4 pr cent of copper when using the ratiosof copper sulfate to alkalinous chloride as stated herein. The reagentsof this invention have the advantage that they are uniform in particlesize and composition; the particle size of the granules can be chosen soas to produce uniform distribution and contact of hydrocarbon during thesweetening step thus allowing more careful control of the operation; andsweetened distillates of improved quality are produced from the processin which the reagents are used.

The sweetening process in which the reagents are used normally comprisescontacting hydrocarbon distillate mixed with air with the coppersweetening reagent at temperatures of approximately 60-120 F., thepreferred range being 7 90 F. The reagent is normally used in granularform but may be used as a powder or slurry in some cases. Thecopper-sweetening step is normally followed by a secondary treating stepin which impurities present in the gasoline as a result of thecopper-sweetening step are removed. In certain instances, such as whensweetening some straight-run gasolines, this secondary step may bedispensed with, but is usually a necessary part of the process. Thereagents used for this purpose include alkali metal sulfides, zincsulfide,

iron sulfide, etc. When using the present reagent in the coppersweetening process, the use of the secondary treating step is intendedwhere such treatment is necessary. The residual air from the primarytreating step is preferably released prior to the secondary step.

The following examples are given to illustrate the applicability of theprocess but should not be construed as limiting it to the exactconditions given therein.

Eazample 1.-A reagent was prepared by heating 6-20 mesh pumice at atemperature of 350 F., separately heating copper sulfate and ammoniumchloride with just enough water to completely dissolve the mixture at atemperature of 200 F., the salts being present in the ratio of 66.?parts of copper sulfate to 33.3 parts of ammonium chloride by weight.The hot solution was sprayed onto the hot pumice in such a manner thata, uniform coating was obtained. The water was permitted to evaporateunder these conditions. It was found that the final reagent containedthe equivalent of 2.05% of copper and cracked gasoline.

14.2% of water. This reagent was found to be satisfactory for sweeteninga Mid-Continent More than 12,000 barrels of sweetened gasoline per tonof reagent was obtained.

Example 2.-The reagent was prepared in a similar manner to thatdescribed in Example 1, except that the weight ratio of copper sulfate-to ammonium chloride was 50:50. This reagent satisfactorily sweetenedthe gasoline. A yield of more than 15,000 barrels of gasoline per ton ofsweetening reagent was obtained.

Reagents prepared in a similar manner, but wherein the weight ratios ofcopper sulfate to ammonium chloride were :60, 37.5162]? and 70:30, wereunsatisfactory as sweetening reagents. The maximum quantity of gasolineproduced by any one of these reagents was approximately 200 barrels perton. The reagent could not be satisfactorily regenerated following thistreatment.

We claim as our invention:

1. A process for manufacturing an oil refining agent comprising heatinga granular carrier to a temperature within the range of approximately250-400 F., mixing with said carrier a solution of copper sulfate and analkalinous chloride, the weight ratio of copper sulfate to said chloridebeing within the limits of approximately :50 and 67:33, said solutionbeing heated to a temperature within the range of approximately l50-250F. and allowing a portion-of the excess water to evaporate.

2. The process of claim 1 wherein the alkalinous chloride is ammoniumchloride.

DAVIS READ, JR. WAYNE L. BENEDICT.

